1. Field of the Invention
The invention relates in general to a liquid crystal display (LCD) and the driving method thereof, and more particularly to an LCD and the driving method thereof which reduce color difference by adjusting the corresponding red (R), green (G) and the blue (B) Gamma Curves of the LCD.
2. Description of the Related Art
Due to the features of low radiation, slimness and compactness, LCD has gained a wide popularity. Referring to FIG. 1, a partial circuit diagram of a conventional LCD is shown. LCD 10 at least comprises a data driver 12 and an LCD panel 14. The data driver 12 is for receiving an original red data signal SR0, an original green data signal SG0 and an original blue data signal SB0 outputted from a TV or computer and correspondingly outputting a red voltage signal VR, a green voltage signal VG and a blue voltage signal VB to the LCD panel 14. The LCD panel 14 respectively drives a red pixel, a green pixel and a blue pixel of the LCD panel 14 to display a corresponding frame according to the red voltage signal VR, the green voltage signal VG and the blue voltage signal VB received.
Referring to FIG. 2, a relationship curve between gray level and pixel luminance when a conventional multi-domain vertical alignment (MVA) LCD is viewed from the front is shown, wherein pixel luminance=Y (to-be-measured gray level)/Y (luminance maximum gray level, 255 for instance)×100%, Y refers to luminance. When the original data signal corresponds to different gray levels, the data driver 12 will generate different the voltage value of the voltage signal accordingly, so the pixel will have different pixel luminance. The correspondence relationship between the gray level and pixel luminance of the red pixel forms a red Gamma Curve GC (R); the correspondence relationship between the gray level and pixel luminance of the green pixel forms a green Gamma Curve GC (G); while the correspondence relationship between the gray level and pixel luminance of the blue pixel forms a blue Gamma Curve GC (B). No overlapping occurs among the red Gamma Curve GC (R), the green Gamma Curve GC (G) and the blue Gamma Curve GC (B). Moreover, when the red pixel, the green pixel and the blue pixel all correspond to the same gray level, i.e., specific gray level GL1, the pixel luminance LB of the blue pixel viewed from the front is higher than the pixel luminance LG of the green pixel viewed from the front, while the pixel luminance LG of the green pixel viewed from the front is higher than the pixel luminance of the red pixel the LR viewed from the front.
Referring to FIG. 3, a relationship curve between gray level and pixel luminance when a conventional MVA LCD is viewed in a squint mode is shown. Let the maximum gray level of the LCD 14 be 255. When viewing the conventional LCD 14 in a squint mode within a gray level range of 50 to 150, the blue Gamma Curve viewed in a squint mode GC′ (B) leads to a maximum difference between the pixel luminance viewed from the front and viewed in a squint mode. For a particular gray level GL1 within the gray level range of 50 to 150, the pixel luminance viewed in a squint mode of the red pixel, the green pixel and blue pixel are LR′, LG′ and LB′ respectively.
Since a large difference exists between the Gamma Curve obtained when the LCD is viewed from the front and when the LCD is viewed in a squint mode, the ratio of LR′, LG′ and LB′ (LR′:LG′:LB′) when the pixel luminance viewed in a squint mode, is different from the ratio of LR, LG and LB (LR:LG:LB) when the pixel luminance viewed from the front. Therefore, when a user views a conventional LCD from the front or in a squint mode, the observed color is different leading to color difference. How to reduce color difference is therefore an essential factor to enhance the display quality of an LCD.